Modern smart phones and navigation devices are typically equipped with mapping capabilities. For example, a user of these devices may use the mapping capabilities to locate a point of interest or to plan for a trip. In addition, smart phone and navigation devices may be equipped with global positioning system (GPS) capabilities. In this case, GPS may be used on these devices to obtain maps of the geographic area at the device's location. Once located, the device may be used to navigate (by driving, using public transportation, walking, etc.) to a destination specified by the user. Specifically, the device may provide turn-by-turn directions and track the progress of the user in real-time on a map by showing a current location of the user.
In the case of public transportation, mapping and navigation services typically rely on transit data supplied by the transit providers. Portions of the transit data may not be consistent with road features. Further, the transit data may be incomplete or lack interactive features useful for navigation.